Ladies briefly dancing in dream (5)
I believe the answer is:
ideal
'dream' is the definition.
(I've seen this before)
'ladies briefly dancing' is the wordplay.
'briefly' means to remove the last letter.
'dancing' is an anagram indicator.
'ladies' with its final letter taken away is 'ladie'.
'ladie' anagrammed gives 'IDEAL'.
'in' is the link.
(Other definitions for ideal that I've seen before include "The best conceivable" , "Most suitable" , "Perfect; visionary" , "Perfect but perhaps unlikely to become reality" , "Benchmark" .)